什么是自动换行并对齐文本文件以使输出看起来像手册页的命令:
All of these system calls are used to wait for state
changes in a child of the calling process, and obtain
information about the child whose state has changed. A
state change is considered to be: the child terminated; the
child was stopped by a signal; or the child was resumed by
a signal. In the case of a terminated child, performing a
wait allows the system to release the resources associated
with the child; if a wait is not performed, then the termi-
nated child remains in a "zombie" state (see NOTES below).
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使用fold
命令指定允许的最大宽度:
perl -e 'print "a"x5, " " for 1..99' | fold -w 30
你得到:(而不是一行)
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa aaaaa
aaaaa aaaaa aaaaa aaaaa
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那就是格罗夫。
(较旧的 Unix 版本使用 NROFF 或 TROFF,但它们都是同一系列中的不同程序。)
请注意,这不是一个对文本文件进行操作的简单命令。它需要在文本中插入格式说明。
事实上,它的运行方式更像是一个编译器。
如果您熟悉 TeX 或 LaTeX,那么您就知道其原理,但是各种 ROFF 风格的程序都有更简单的命令语言。